We propose to undertake studies directed towards the discovery and identification of new antibiotic and anticancer natural products from marine fungi. Most of the antibiotics and antitumor agents currently in use have been discovered through extensive studies of the chemistry of terrestrial microorganisms. By comparison, the chemistry of marine microorganisms remains largely unexplored. We intend to acquire pure strains of targeted marine fungal species from public and private culture collections, cultivate them using techniques already established in our laboratory, and screen the resulting culture filtrates for antimicrobial and potential antitumor activity. Modern chromatographic and spectroscopic techniques will be used in purifying and identifying metabolites which show promising activity in our assays. All phases, including in vitro bioassays, will be conducted in our own laboratory. The results of preliminary studies will be used to direct further investigations by suggesting classes of mrine fungi on which to concentrate our efforts. Evaluation of hypothesized approaches to future research will be carried out based on the results of this sampling of marine fungi. Through these studies, we expect to add to the limited knowledge of the chemistry of these organisms while exploring their potential as sources of pharmacologically useful compounds.